The proposed project is a partnership between prevention scientists and the Cherokee Nation Behavioral Health Services to create, implement and evaluate a new, integrated community-level intervention designed to prevent underage drinking and associated negative consequences among American Indian and white youth living in rural high-risk underserved communities. This trial will take place in northeastern Oklahoma, an area suffering from high rates of poverty and substantial health disparities. The proposed intervention builds directly on the results of multiple previous experiments with two distinct approaches-community environmental change and brief intervention and referral-evaluated alone and in combination using a factorial design. Direct- action community organizing, documented as effective in multiple previous randomized trials, will be used to address community issues related to alcohol use and commercial and social access to alcohol among adolescents. Our design and implementation of brief interventions differs in a fundamental way from typical implementations. Instead of SBIRT implemented in select limited numbers of clinics, emergency departments or schools, we will design a community-wide SBIRT intervention. The population-level brief interventions will include five key components: (1) brief one-on-one screening and motivational interviewing sessions, (2) gatekeeper training, (3) peer leader training, (4) family postcard campaign, and (5) community-wide media campaign. Five key research design elements optimize causal inference and experimental evaluation of the intervention effects: (1) a controlled interrupted time-series design, (2) random selection of towns, (3) random assignment to study condition, (4) a factorial design, and (5) multiple comparison groups. The primary design feature of this randomized trial is a controlled interrupted time-series design. The large number of repeated measures (a time-series) substantially increases internal validity (i.e., strength of causal inference) as well as statistical power over conventional pre/post community trial designs. Repeated assessments will measure implementation fidelity for each intervention component, and measure key proximal as well as the primary ultimate outcomes through survey, observation and archival sources. The primary study sample will include all high-school students within study towns. Weekly and monthly measurements will produce a time-series design with observations of youth nested within town over the four-year period. In addition to repeated cross-sectional samples, we will use participant identifiers to track the embedded cohorts over the four years. This innovative project, involving a strong partnership between established prevention scientists and leaders of the Cherokee Nation Behavioral Health Services, has the potential to transform alcohol prevention research and practice. Despite advances in prevention science and practices in recent decades, the U.S. continues to struggle with significant alcohol-related risks and consequences among youth. The proposed project will provide a rigorous evaluation of a new, integrated community-level preventive intervention. PUBLIC HEALTH RELEVANCE: The proposed project is a close partnership between prevention scientists and the Cherokee Nation Behavioral Health Services to create, implement and evaluate a new, integrated community-level intervention designed to prevent underage drinking and associated negative consequences among multi-ethnic youth living in rural, high-risk underserved communities. The intervention will include community strategies to reduce access to alcohol and high-risk situations, and community-wide implementation of brief interventions and referral. This innovative project has the potential to transform alcohol prevention research and practice, as the U.S. continues to struggle with significant alcohol-related risks and consequences among youth.